Abrasive surfacing disk



Jan; 22, 1935.

J. A. MALCOLM ABRASIVE SURFACING DISK Filed Feb. 20, 1933 fiver/Z722 JamesfljUwlcolfi Patented Jan. 22, 1935 UNITED STATES PATENT OFFICE ABRASIVE SURFACING DISK James A. Malcolm, Chicago, 111., assignor to Julius S. NeaIe Chicago, 111.

Application February 20, 1933, Serial No. 657,535

2 Claims. (01. 51-195) This invention relates to improvements in an A still further object of this invention is to abrasive surfacing disk, and is more particularly provide a composite abrasive disk of the chardirected to an improved composite abrasive disk acter described which is formed of a compressifor use in the surfacing and abrading of metal, ble material having a relatively thick body for 5 wood and other surfaces, on articles such as sheet providing the desired flexibility to permit the disk 5 metal bodies, floors and numerous other articles to bend and flex, but at the same time being having a surface which must be cut down to a capable of withstanding alternate bending or flexsmooth and generally level condition. ing at a high rate of speed and without the sepa- In the operation of such devices, the disk is ration of one layer of the composite material from 0 secured at its center to a'rotating shaft and the another, said disk being also capable of being outer portion of the disk, which is covered on its resurfaced with said abrasive grains whenever operating surface with a suitable abrasive, is found necessary or desirable. then pressed against the work, and particularly A still further object of this invention is to prowhere the operation is carried out on metal there vide a composite abrasive disk of the character is an extremely high resistance to the rotation of described having a body of compressible ma- 15 the disk by reason of the cutting of the abrasive terial, to one surface of which is permanently grains into the metal. The result is that the securedalayer'of abrasive grains, said body being disks, in order to have a suitable life, must be capable of being resurfaced from time to time as made of extremely strong tough material, which such abrasive grains are worn away in use.

at the same time must have a certain degree of A still further object of this invention is to 20 flexibility to permit them to flex and bend as the provide a composite abrasive disk of the charsupporting pad compresses or bends. It is essenacter described which is simple in construction tial that the material be capable of withstanding and which may be produced along lines conalternate bending or flexing at a high rate of venient for low cost manufacture, and which may speed and without the separation of one layer be highly eflicient for carrying out the purposes 25 of the composite material from another. for which it is designed.

It is, therefore, the main object of this inven- With the foregoing and other objects in view, tion to provide an improved composite abrasive which will appe as the description proceeds, the disk of the character described which is formed invention consists in certain novel features of ofacompressible materialhavinganabrasive surconstruction, arrangement and combination of 30 face so secured thereto as to withstand alternate parts, hereinafter more fully described, illustrated bending or flexing at a high rate of speed within the accompanying drawing, and. particularly out the separation of one layer of the composite p in Out in the pp claims, it being material from another. understood that various changes in the form,

Another object of this invention is to provide a proportion, size and minor details of the struc- 35 composite abrasive disk of the character described ture may be made without departing from the including a compressible felt body, to one surface p t Sa fi y of the advantages of h 4 of which is securely fastened a canvas disk to the invention.

free surface of which canvas disk is adhesively For the purpose of facilitating an understandsecured a layer of abrasive grains. ing of my invention, I have illustrated in the fore- 40 A further object of this invention is to provide going raw ng a pr d m d t th r f. a composite abrasive disk of the character defrom an insp thereof When considered in scribed, including a relatively thick body of comconnection with the following d p my i pressible material, upon one surface of which is vention, its d of construction, a b y a d Y adhesively secured a layer of grains, said layer of operation, and many of its advantages, should be 45 grains extending to and covering the outer edge readily understood and pp A of saiddisk. Referring to the drawing in which the same A still further object oi this invention is to prohara t s f r r e ar mp y d t indicate vide a composite abrasive disk of the character correspo d Similar parts throughout the described which is formed of a compressible maseveral figures 0f t awin terial, toone surface of which is rigidly secured Figure l is a view in perspective of myimproved by stitching or the like a canvas disk, and to the surfacing disk, the same being shown connected outer surface of said canvas disk is adhesively to an apparatus by means of which the disk is secured a layer of grains, said layer of grains also rotated;

covering the outer free edge of said disk. Fig. 2 is a transverse central section through 55 one form of my improved disk, being taken on line 2-2 of Fig. 4;

Fig. 3 is a transverse central section through a modified form of my improved disk, taken on line 3-3 of Fig. 5;

Fig. 4 is a bottom plan view of the modification shown in Fig. 2; and

Fig. 5 is a bottom plan view of the modified form shown in Fig. 3.

As already stated, the present invention is directed primarily to the provision of an abrasive disk for use on a rotatable shaft. As shown in Fig. 1, there is provided a shaft 1 upon the free end of which is mounted my improved flexible abrasive covered disk 10, said shaft and disk being secured to a housing 2 and are rotated by the flexible shaft 3 which is carried to the housing 2 where it drives the shaft 1 through suitable bevel gears (not shown). The housing 2 is provided with a suitable handle 4 by means of which the operator holds the device against the work, thus giving him a quite accurate control of the operation as he can both vary the pressure of the abrasive disk against the work or vary the angle at which the apparatus works, and also move the operating portion of the abrasive disk from point to point over the surface of the panel in order to prevent the warping'which results in the case of certain metal panels if the disk is held in one position too long.

In the form illustrated in Fig. 2, my improved disk comprises a body 11 which may be formed of any suitable compressible material, such as felt, which had been securely stitched together by means of stitching l2 and then compressed to the desired thickness. To one surface of this pad 11 is then secured a layer of adhesive 13 to which latter is then secured a layer of abrasive grains 14, said layer of adhesive and grains extending to the outer edge 15 of the disk. The composite structure thus formed is provided with a central opening 16 which illustrates the simplest means for permitting attachment of this disk to the driving shaft 1.

From my experience in the manufacture and sale of abrasive disks of this character, and from numerous tests conducted with these disks, I have found that a composite disk of the structure referred to above and more particularly illustrated in Fig. 2, will possess all of the qualities required in such an article, that is, flexibility, the torsional strength under the resistance set up by the engagement between the abrasive grains and the work, and the life which is necessary for economical operation of such machines under the above strains and under alternate fiexure when the speed of rotation does not exceed about seventeen hundred revolutions per minute.

However, when it is desired to produce a disk of this character which will possess the above qualities and will stand up under a speed of revolutions greater than seventeen hundred revolutions per minute, say up to and including thirty-five hundred revolutions per minute, I have found it desirable to secure the abrasive grains to a canvas disk and then adhesively secure the layer to the felt pad. Thus in the modification illustrated in Figs. 3 and 5, there is shown a pad 20 which is made up of compressible material, such as felt, which material is securely stitched together by means of the radial rows of stitches 21 and then be rigidly and permanently secured to the felt body.

The disk of canvas 23 is substantially of the same shape and size as the felt pad, and to the outer surface thereof is applied a layer of adhesive 25 to which layer is secured a layer of abrasive grains 26. The abrasive 26 is adapted to extendaround the outer rim of the disk, as shown at 27 in Fig. 3. The composite structure thus formed is provided with a central opening 28, which illustrates the simplest means for permitting attachment of this disk to a supporting and driving shaft.

From the above it will be apparent that I have provided an abrasive disk which will have the desired degree of flexibility to permit the same to bend and flex while at the same time being capable of withstanding alternate bending or flexing at a high rate of speed and without the separation of one layer of the composite material from another. It will also be noted that by reason of the pad of felt provided for the abrasive material a cushioning efi'ect will be produced in the operation of the device, thereby eliminating the necessity for a cushioning pad of rubber or the like heretofore used with devices of this character.

A further feature of this construction is that the pad may be resurfaced from time to time as the abrasive is worn therefrom in the use of the pad. This is a feature which has not been possible with abrasive disks heretofore produced, and as a result of this feature a considerable saving may be made in the operation and use of surfacing disks of this character.

It is believed that my invention, its mode of construction, assembly and operation, and many of its advantages should be readily understood from the foregoing without further description, and should also be manifest that while preferred embodiments of the invention have been shown and described for illustrative purposes, the structural details are nevertheless capable of wide variation within the purview of my invention as defined in the appended claims.

What I claim and desire to secure by Letters Patent of the United States is:

1. A composite surfacing disk comprising a pad of compressible material which had been compressed and stitched to form a relatively stiff and rigid element, a sheet of cloth secured to said pad both by stitching and adhesive extending over its entire area, and a coating of grains adhesively secured over the free surface of said cloth and over the outer edge of said pad.

2. A composite surfacing disk, comprising a pad of compressible material which had been compressed and stitched to form a relatively stiff and rigid element, a coating of adhesive substance applied to said element and extending over the entire surface of one face thereof and the outer periphery thereof, and a coating of grains adhesively secured to said adhesive coating to. cover the entire area thereof, including the outer periphery of said element.

JAMES A. MALCOLM. 

